I'm a bit of a mixed bag on achievements. I'll give my all to getting achievements what most people would go "but why?" about, stuff like sitting there and grinding my brain away as I plough through Halo Reach on Solo Legendary with no "mini-hacks" (where the player messes around with tracking forwards and back to load/unload enemies on the map making certain levels a lot easier than they are/ought to be) though perhaps ironically I find the mental challenge of working out the way through those sort of challenges fun but I do know when to walk away, for example CoD 4 Modern Warfare I have 980 out of 1000 points on. I could go for the final 20 which was simply by completing the bonus mission at the end of the game "Mile High Club" on the highest difficulty. I have the skillset to do that mission given however I would have to figure out how/rely on some luck to push through 30 - 40 enemies on the highest difficulty in under 90 seconds and then finish the mission's final encounter with a headshot perfectly placed I decided that it wouldn't be worth it. I had 960 achievements on Resident Evil 5 prior to the release of the DLC and could easily in 15 mins or so boosted that to 980/1000 but decided it wouldn't be worth it.

However most games I play I will generally not care about every achievement in the game and will rely upon enjoying the game. That being said I really need to re-purchase Red Dead Redemption, GTA IV and Saints Row 3, I understand why I had to sell those games but it bothers me.